This project is directed at understanding the mechanisms of HIV-1 binding, entry, replication and assembly, particularly in macrophages, and in developing an effective strategy to prevent and/or inhibit infection. Immunodeficiency, the consequence of HIV-1 infection, predisposes the host to opportunistic infections. In turn, opportunistic infections influence target cell susceptibility to HIV-1 infection and replication. Using M. avium as a model co-pathogen, we have defined multiple viral permissive factors. Moreover, immune activation as typicallly occurs in tonsils and non-infectious mucosal inflammatory lesions may also be associated with proximal sites of viral replication. These connections between activation/inflammation and enhancement of HIV-1 infection warrant further elucidation of the factors promoting permissiveness to HIV-1. Infection of human macrophages in an in vitro model revealed a pattern of signal transduction, expression of immediate early genes, and downstream genes associated with viral replication by cDNA microarray analyses. As the association between signaling cascades, gene transcription and macrophage-specific viral dynamics is elucidated, our goal is to identify new cellular targets to interfere with HIV replication. In this regard, one of the genes consistently upregulated in HIV-1 infected macrophages is a differentiation marker and cell cycle regulator, which appears to be influenced by the virus and necessary for its optimal replication. In contrast to CD4+ lymphocytes, HIV-1 infected macrophages typically resist cell death, support viral replication, and consequently facilitate HIV-1 transmission. Multiple contributing factors may favor the macrophage as a resilient host, not only supporting infection by HIV-1, but also promoting replication and persistence of this member of the lentivirus subfamily of primate retroviruses. An encounter between macrophages and R5 virus in vitro engages a signal cascade eventuating in transcriptional regulation of multiple genes including those associated with host defense, cell cycle, NFkB regulation and apoptosis. Importantly, enhanced gene expression is transient, declining to near control levels and during this quiescent state, the virus continues its life cycle unimpeded. However, when viral replication becomes prominent, an increase in host genes again occurs under the orchestration of viral gene products. This biphasic host response must fulfill the needs of the parasitic virus as viral replication activity occurs and leads to intracellular and cell surface associated viral budding. Inroads into understanding how HIV-1 co-opts host factors to generate a permissive environment for viral replication and transmission to new viral hosts may provide opportunities for targeted interruption of this lethal process. To elucidate how the virus commandeers macrophage intracellular machinery for its benefit, HIV-1 infected human monocyte-derived macrophages were analyzed for viral-induced gene transcription by multiple parameters including cDNA expression array. HIV-1 infection induced the transcriptional regulation of genes associated with host defense, signal transduction, apoptosis and cell cycle, of which the cyclin-dependent kinase inhibitor 1A is the most prominent. mRNA and protein expression followed a bimodal pattern with maximum levels occurring during active HIV-1 replication. Treatment of macrophages with anti-sense oligonucleotides reduced HIV-1 replication. Furthermore, a synthetic triterpenoid and peroxisome proliferator-activated receptor gamma ligand, 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), known to influence the kinase inhibitor expression, suppressed viral replication. These data implicate this host cell molecule as a pivotal macrophage facilitator of viral replication. Moreover, regulators of this molecule, such as CDDO, may provide an interventional approach to modulate HHIV-1 replication. To this end, we received a Bench-to-Bedside Award to pursue clinical trials of CDDO in the treatment of AIDS/lymphoma.